Lattice tower supporting interior dipoles with reduced interference



United States Patent 12 Claims. (a. 343-796) The present inventionrelates to an antenna system with an antenna support constructed in theform of a lattice mast or the like, in connection with which theradiators, for instance full-wave dipoles, are arranged substantiallywithin the mast.

An antenna system is known in which the radiators which are fed aswhole-wave dipoles are arranged in the form of a polygon which in itsturn is arranged within the corner posts of a supporting lattice mast.The individual radiators are in this case connected in the voltage nodeby special struts with the corner posts of the mast. The horizontalmembers of the mast are in the known systems arranged approximately inthe center between the radiator polygons. In such antenna systems, theinfluence of the mast on the radiation can be kept very small, as longas the length of the side of the square mast does not exceed certainlimits referred to the wavelength of the energy radiated. If, on theother hand, with constant external dimensions of the mast, thewavelength of the energy radiated is reduced or in case of constantwavelength, the dimensions of the mast are increased, then changes areproduced in the radiation pattern, as a result of electrical resonances,particularly on the horizontal members of the mast.

The object of the present invention is in particular to make possible,also for large mast cross-sections as compared with the wavelength, theuse of radiators arranged on the inside of lattice masts without theradiation pattern being changed by the influence of the mast. The samemasts can thus be used for larger frequency ranges, for instance for anentire television band, and more stable constructions are obtained, suchas is desirable in particular for antenna systems of high gain andcorrespondingly great structural heights. Such antenna systems cantherefore also serve as supports for other stacked antennas of otherfrequency ranges. While in the known systems with radiators arrangedwithin the mast, no cross-bracings were as far as possible arranged inthe vicinity of the radiators, and the horizontal diagonal bracesbetween the corner posts of the mast were therefore arranged as far aspossible in the center between two radiator polygons, arranged one abovethe other, the present invention, differing from these concepts, pointsout an entirely different manner by which a solution of the mechanicaland electrical problems of such an antenna system is possible.

In accordance with the present invention, which is concerned with anantenna system of the initially indicated type, the radiators arearranged in the region of a horizontal diagonal brace serving for thereinforcing of the corner posts of the mast, and are held preferablydirectly or indirectly to the members of the horizontal diagonalbracing. It has surprisingly been found that with mast cross-sectionswhich go beyond the size customary heretofore with similar antennasystems, disturbances in the radiation patterns, particularly in case ofomnidirectional radiation, can be avoided. As compared with the knownantennas with radiators arranged within the mast, there is also theadditional advantage that the members of the horizontal diagonal bracingcan simultaneously also be ice used as direct or indirect mounts for theantenna elements so that additional supports are no longer necessary.

Particularly favorable arrangements of the radiators, referred to themembers of the horizontal diagonal bracing are obtained if the radiatorsextend transversely to the members immediately adjacent to them and onwhich they are preferably also mounted. It is furthermore advisable todevelop the horizontal diagonal bracing as simple crossed bracing inconnection with which the radiators are arranged at right angles to themembers bearing them. When using whole-wave dipoles as radiators of theantenna system, the latter can be conductively connected at the voltagenode or near it to the members of the horizontal diagonal bracing.

In order to obtain radiation patterns which exhibit the least possibleinfluence by the mast, it is advisable also to select for the sidebracing extending on the sides of the mast special arrangements of themembers which result in suflicient mechanical strength and exert aslittle disturbing effect electrically as possible.

An advantageous further development of the invention accordinglycontemplates for the side members extending on the sides of the mastbetween the corner posts, a simple zig-zag bracing, in the corners ofwhich are arranged the horizontal transverse bracings bearing radiators.In this connection, it is advisable to arrange the zig-zag lateralbracing in such a manner as to produce zig-zag strips which extendparallel to each other in the developed view of the side bracing. Theinfluence of the side bracing on the radiation characteristic isparticularly slight if the inclination of the members of this bracing isselected as large as possible, and if a radiator polygon lies in eachcorner formed by the members of the side bracing. In cases in whichsufficient inclination for the members of the zigzag shaped side bracingis not possible, disturbing resonance phenomena can be prevented by theprovision of cavity resonators on the members of the side bracing.

Further details of the invention will be explained with reference to theaccompanying drawings showing an embodiment of an antenna mast servingfor the radiation of meter or decimeter waves, and particularly waves inthe ultra-shortwave radio range or the television range.

FIG. 1 shows in perspective a lattice mast 1 of square cross-section,the corners of which are formed by the corner posts 2, 3, 4 and 5. Theradiator elements 6, 7, 8 and 9, which operate as whole-wave dipoles,are also arranged in a square within the mast in such a manner that thecorners of the mast and the corners of the square formed by the radiatorare staggered 45 from each other. The corners of the square formed bythe radiators lie accordingly in the center of the side planes of themast 1. In order to obtain a strongly focused vertical characteristic, aplurality of such radiator polygons are arranged one above the other, ofwhich only the system formed of the radiators 14, 15, 16 and 17 isshown. The horizontal diagonal 'bracings necessary for the mechanicalstiffening of the mast consist of the members 22 extending from thecorner post 2 to corner post 4, and the members 21 connecting cornerposts 3 and 5. The radiators 6, 7, 8 and 9, and 14, 15, 16 and 17respectively are arranged in the region of the members 21 and 22 formingthe horizontal diagonal bracing, which members when whole-wave dipolesare used can be conductively connected with the members 21 and 22respectively directly in the voltage node of the voltage distribution ofa standing wave designated in FIG. 2 by the reference letter U, or inits vicinity.

When using other radiator arrangements, the mechanical mounting of saidradiators can also be effected by the members 21 and 22, in which casethe radiators should be supported on the members with the use ofinsulators.

The side bracing provided on the sides of the mast consists of simpleuncrossed members 23, 24, 25 and 26 which are arranged in zig-zag formand the corners of which lie in each case in the region of the radiatorpolygon and thus in the region of the horizontal diagonal bracings. Inthis way, disturbing resonances at the members of the side bracing aresubstantially avoided. The members of the side bracing on the individualsides of the mast are so associated with each other that in developedview zig-zag strips extending parallel to each other are formed. Theradiation patterns of such antenna systems lie, even in case of sidelengths of the mast corresponding approximately to an averagewavelength, within the sphere of the requirements established foromni-directional patterns.

FIG. 2 shows the lattice mast as seen from the top thereof. Thefull-wave dipoles 14, 15, 16 and 17 are placed under voltage via thefeed lines 27 and 28. The balancing and transformer units 31, 32 areadvantageously arranged between the radiator planes and can in givencases be fastened to a central ladder 30. The wholewave dipoles extendtransversely to the members 21, 22 of the horizontal diagonal bracing,which support them and form therewith an angle of 90. In this way, thewhole-wave dipoles extend in each case parallel to the member of thehorizontal diagonal bracing which does not support them and which liessymmetrically in the center between the whole-wave dipoles which extendin each case parallel toeach other. In this manner are avoideddisturbing influences from the struts of the horizontal diagonal bracingon the radiation properties of the radiator polygon.

The feeding of these radiators is advantageously effected by causing acircular current to develop on the radiator polygon, whereby theradiators lying opposite each other are traversed by currents of thesame magnitude but in opposite directions. The horizontal diagonalbracing is developed as a simple cross-wise bracing. The center point ofthe horizontal diagonal bracing formed by the members 21 and 22 and thecenter point of the radiator polygon both lie in the axis of the mast.The device for the connecting in parallel of the four whole-wave dipolesof the cube, as well as for the unbalancing for connection to a feedcable is suitably fastened to a frame between the two dipole planes orto a ladder which is preferably arranged at the center.

Every two cubes lying above each other are advantageously mutuallydisplaced by 90 in the vertical axis.

Changes may be made within the scope and spirit of the appended claimswhich define what is believed to be new and desired to have protected byLetters Patent.

We claim:

1. An antenna system comprising an antenna supporting mast oflattice-type construction having corner posts and horizontal diagonalbrace members which serve to stiffen such corner posts, and whole wavedipole radiators arranged substantially within the mast, disposedadjacent the corners of the mast and supported on such diagonal bracemembers.

2. Antenna system according to claim 1, wherein the radiators extendtransverse to those members of the horizontal diagonal bracing whichthey'immediately adjoin and on which they are mounted.

3. Antenna system according to claim 2, wherein the horizontal diagonalbracing is constructed as a simple cross-type bracing, perpendicular tothe members of which are arranged the radiators held thereby.

4. Antenna system according to claim 3, wherein the radiators are fed bypairs as whole-wave dipoles, said radiators being arranged in a polygonwith corners staggered with respect to the corner posts of the mast.

5. Antenna system according to claim 4, wherein the radiators form asquare which is staggered 45 with respect to the lattice mast which islikewise developed with a square cross-section.

6. Antenna system according to claim 5, wherein the centerpoint of thehorizontal diagonal bracing and the centerpoint of the radiator polygonboth lie in the axis of the mast.

7. Antenna system according to claim 4, wherein each of the whole-wavedipoles is conductively connected in the vicinity of the voltage nodethereof with the members of the horizontal diagonal bracing.

8. Antenna system according to claim 1, wherein the balancing device andthe distributing lines are arranged between the radiator planes and arefastened to a central ladder.

9. Antenna system according to claim 1, wherein the side bracingextending between the corner posts on the sides of the mast is developedas a simple zig-zag shaped bracing in the corners of which are arrangedthe horizontal transverse bracings supporting the radiators.

10. Antenna system according to claim 9, wherein the zig-zag sidebracing is so arranged that in developed view, there are producedzig-zag strips extending parallel to each other.

11. Antenna system according to claim 1, wherein every two cubes locatedone above the other are mutually displaced by in the vertical axis.

12. Antenna system according to claim 10, wherein a radiator polygon isdisposed in each corner formed by the members of the side bracing, theinclination of the zig-zag bracing being such that disturbing resonancephemomena is reduced.

References Cited by the Examiner UNITED STATES PATENTS 2,254,697 9/1941Godet 343798 X 2,583,287 1/1952 Andrews 343875 2,771,606 11/1956Kandoian 343-890 FOREIGN PATENTS 332,352 8/ 1958 Switzerland.

OTHER REFERENCES Electronics, August 1955, pp. and 131.

HERMAN KARL SAALBACH, Primary Examiner.

ELI LIEBERMAN, Examiner.

1. AN ANTENNA SYSTEM COMPRISING AN ANTENNA SUPPORTING MAST OFLATTICE-TYPE CONSTRUCTION HAVING CORNER POSTS AND HORIZONTAL DIAGONALBRACE MEMBERS WHICH SERVE TO STIFFEN SUCH CORNER POSTS, AND WHOLE WAGEDIPOLE RADIATORS ARRANGED SUBSTANTIALLY WITHIN THE MAST, DISPOSED